Inkjet printers (referred in the following as “printers”) are known as printing apparatuses for forming images by ejecting ink onto a paper serving as a medium. These printers repeat in alternation a dot formation operation of forming dots on a paper by ejecting ink from a plurality of nozzles, which move in the movement direction of a carriage, and a carrying operation of carrying the paper in an intersecting direction that intersects the movement direction (hereinafter, referred to as the “carrying direction”) by a carry unit. Thus, a plurality of raster lines made of a plurality of dots in the movement direction are formed in the intersecting direction, to print an image.
Now, with such a printer, darkness non-uniformities extending parallel to the movement direction of the carriage can be occasionally observed in images made of a multitude of raster lines. The reason for such darkness non-uniformities lies mainly in the machining precision of the nozzles. More specifically, there are two cases: the case of variations in the ink ejection amount among the nozzles, and the case that the positions at which dots are formed on paper by ejecting ink from the nozzles (referred to as “dot formation positions” in the following) deviate in the carrying direction from the target positions.
Accordingly, in the printing method described in JP H06-166247A, a correction pattern with a specified single darkness is first printed on the paper. Next, the darkness of the printed correction pattern is read in, and printing is performed while performing a darkness correction based on the read data.